The White House has confirmed the Trump and Buhari phone call. During The White House press Briefing on Tuesday, 14, February, 2017.
"The President was pleased to launch the Canada-United States Council for the Advancement of Women Entrepreneurs and Business Leaders by holding a roundtable discussion here at the White House. Together with Prime Minister Trudeau, his daughter Ivanka, the President discussed the unique challenges that women face in the workplace with an incredible group of successful and respected female business executives from both countries. A full list of the participants is available through the pool.
In addition to his in-person meetings with the prime ministers of Japan and Canada, the President also recently had phone calls with the presidents of Tunisia, Peru, Nigeria, Colombia and South Africa. Readouts are available on all of those calls" He said